app.js

const express = require('express');
const path = require('path');
const favicon = require('serve-favicon');
const logger = require('morgan');
const cookieParser = require('cookie-parser');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');

if (process.env.NODE_ENV !== 'production') {
  require('dotenv').load();
}
const port = process.env.PORT;

//routes
const products = require('./api/routes/products');
const orders = require('./api/routes/orders');
const users = require('./api/routes/users');

//mongoose connetion
const uri = process.env.MONGO_ATLAS_CLOUD;
mongoose.connect(uri, {
    useNewUrlParser: true
  })
  //.then(result => console.log(result))
  .catch(err => {
    console.log(err);
    res.status(500).json({
      message: 'Sorry there is some issue with database connection!',
      error: err
    });
  });
mongoose.Promise = global.Promise;

const app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use('/uploads', express.static('uploads'))

//Cross Origin Resource Sharing(CORS) -> Security issues
app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");

  res.header(
    "Access-Control-Allow-Origin",
    "Origin, X-Requested-With, Content-Type, Accept, Authorization"
  );
  if (req.method === 'OPTIONS') {
    res.header('Access-Control-Allow-Origin', 'PUT, POST, DELETE, PATCH');
    res.status(200).json({});
  }
  next()
});

app.use('/', products);
app.use('/orders', orders);
app.use('/user', users);

// catch 404 and forward to error handler
app.use((req, res, next) => {
  const err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use((err, req, res, next) => {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use((err, req, res, next) => {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

app.listen(port, (err) => {
  if (err) {
    console.log(err);
  }
  console.log(`Server is running on port ${port}`);
});

module.exports = app;